Ahhh...
With such a mix of parts used in steel Colnago bike frames for a half century... Anything goes

Anybody have Gipiemme dropouts in a Colnago?
I doubt one would find Tange or Simplex dropouts in a Colnago.

Anyway, it is still important to see what it is. With the frame coming from Italy... I'm guessing that an Asian clone would be less likely which could make it more difficult to rule out a fake.